Piriformis syndrome affects the sciatic nerve creating pain that centers in the butt and often runs down the affected leg. When the piriformis muscle, which connects from outside of the femur (leg) bone to the front portion of the sacrum, goes into spasm or is habitually tight, it can press on the sciatic nerve creating the afore-mentioned pain.
Another aspect of a tight piriformis muscle is that it constricts the sacroiliac (SI) joint which can cause a different kind of pain than piriformis syndrome. Sacroiliac joint pain is as common, if not more common, than piriformis syndrome. It can manifest in a number of ways—as a pulling sensation or a dull ache or even a mild, or not so mild, burning feeling. The piriformis muscle attaches to the sacrum just below the sacroiliac joint so its tone or lack thereof is always going to affect the joint.
The sacroiliac joint is the place where the sacrum meets the ilium of the hip. The hip bone is composed of three bones – ilium, ischium, pubis— that are separate at birth but fuse together in early childhood. The sacrum is the triangular bone between the two hip bones (the sacrum is five separate bones at birth that later fuse). It is both the base of the spine and center of the pelvis at the back. It fits between the two hip bones, connected by the sacrotuberous ligament which also connects the pelvis to the legs and back.
The piriformis is a very tricky muscle. I meet very few people with happy piriformii. The piriformis tends to be too tight or too loose and rarely finds the happy medium of good tone. I fall into the weak piriformis category. On the surface it might seem that this is a positive. I have a killer first position for ballet and I flop into a very deep pigeon pose without any feeling of restriction. I don’t feel anything at all in the pose because there is very little tone in my piriformis or my gluteal muscles (woe is me!).
Someone with a tight piriformis will most likely hate pigeon pose. Trying to stretch a tight piriformis in pigeon is usually a searing pain in the butt as the stretching leg tries to extend out of the hip. The middle ground would be inhabited by someone who didn’t feel the piriformis at all in the pose, but can’t just flop the pelvis to the floor.
Habitual turn out is the modus operandi of both the weak and the tight piriformis which is the tricky part. Everyone should stand and walk with relatively parallel feet which would indicate a balanced piriformis. Instead most people are turned out to one degree or the other which has to affect the tone of the piriformis.
Piriformis syndrome is about more than just a tight muscle. The muscle usually goes into spasm which is what causes it to press against the sciatic nerve and this can happen with a weak or tight piriformis muscle. What this means is that you can have an unhappy sacroiliac joint without suffering from piriformis syndrome but pretty much any time you have piriformis syndrome the sacroiliac joint will be compromised.
The video above is an excellent release for both the sacroiliac joint and the piriformis muscle. The essence of release work is to allow a muscle or joint to stop working and let go, often with the help of gravity. If you stay in this pose long enough it will help to bring relief to the unhappy muscles and joint of the pelvis.